# Full text of "Text Book Of Mechanical Engineering"

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```474

Velocity.

I!'?!

With an original velocity v the distance is found by adding the
two areas at r>, Fig 434.    (See p. 1099.)

A

4\secs.

M"23

C         sec^-

Uniformly Retarded Velocity is a similar case to D, the
final velocity and total distance being found by subtraction of
areas, as at E, and are vl - v2 and sl - ^respectively.

Collating results, with ^ as original and z>2 as final velocities,

U.A.V. from rest.
U.A.V. with original velocity.
U.R.V.

v^ft
J&-^+/'
^2 =  *'l  //

s = J//»
>'='/#! +' ^//2
*=/*!- i//a

V* = 2/S
V<? = ^2 + 2/V
^22= »!2 2/J

Example 4p.  A locomotive and train weighing 100 tons start on
a level, and attain a speed of 60 miles per hour within one minute.
What was the mean pull exerted ?

^        , x     -

From ft)   / - 7 -

and Pull in Ibs. -       =

Io° x

22

-     . IO266 Ibs.

32 x 15

or 4-6 tons, neglecting friction. ,

Conservation of Momentum;  Two balls, A and B,
Fig. 435, raised simultaneously, are allowed to fall, strike, and
rebound. The duration of shock is called the impact, and it is```